Process for using dehydration tower condensate as a purification makeup solvent

Patent metadata

Field	Value
Publication number	US-9260370-B2
Application number	US-201414585520-A
Country	US
Kind code	B2
Filing date	Dec 30, 2014
Priority date	Dec 30, 2013
Publication date	Feb 16, 2016
Grant date	Feb 16, 2016

Abstract

Processes for manufacturing purified aromatic carboxylic acids include: oxidizing a substituted aromatic compound in a reaction zone to form a crude aromatic carboxylic add; transferring a vapor phase from the reaction zone to a separation zone, the vapor phase containing water and a plurality of organic compounds including at least one oxidation by-product; withdrawing an organic-depleted water stream from the separation zone and combining at least a portion of the organic-depleted water stream with at least a portion of the crude aromatic carboxylic acid in a purification zone; and purifying the crude aromatic carboxylic acid in the purification zone.

First claim

The invention claimed is:

1. A process for manufacturing a purified aromatic carboxylic acid comprising:
oxidizing a substituted aromatic compound in a reaction zone to form a crude aromatic carboxylic acid;
transferring a vapor phase from the reaction zone to a separation zone, the vapor phase comprising water and a plurality of organic compounds including oxidation by-products of the substituted aromatic compound;
removing a high pressure vapor phase from the separation zone, the high pressure vapor phase comprising water and being substantially free of oxidation by-products of the substituted aromatic compound;
withdrawing an organic-depleted liquid water stream from the separation zone, the organic-depleted liquid water stream being substantially free of oxidation by-products of the substituted aromatic compound;
combining at least a portion of the organic-depleted liquid water stream with at least a portion of the crude aromatic carboxylic acid in a purification zone; and
purifying the crude aromatic carboxylic acid in the presence of said at least a portion of the organic-depleted water stream in the purification zone to form a purified aromatic carboxylic acid.

2. The invention of claim 1 , wherein the organic-depleted liquid water stream is directed to the purification zone without further treatment to remove organic impurities.

3. The invention of claim 1 wherein the oxidizing comprises contacting the substituted aromatic compound with gaseous oxygen in a liquid phase oxidation reaction mixture comprising a monocarboxylic acid solvent, water, and a catalyst composition.

4. The invention of claim 3 wherein the organic-depleted liquid water stream comprises monocarboxylic acid solvent.

5. The invention of claim 4 wherein the monocarboxylic acid solvent comprises acetic acid.

6. The invention of claim 1 wherein the organic-depleted liquid water stream comprises less than 0.05 wt % alcohol.

7. The invention of claim 1 , wherein the organic-depleted liquid water stream comprises less than 0.05 wt % alkyl ester.

8. The invention of claim 1 wherein the separation zone comprises a first dehydration tower and a second dehydration tower coupled to an output of the first dehydration tower.

9. The invention of claim 8 wherein the second dehydration tower comprises a side draw configured for egress of the organic-depleted liquid water stream.

10. The invention of claim 1 wherein the aromatic carboxylic acid is terephthalic acid.

11. The invention of claim 1 wherein the aromatic carboxylic acid comprises terephthalic acid and the oxidation by-products of the substituted aromatic compound comprises paratoluic acid.

12. The invention of claim 11 wherein the organic-depleted liquid water stream comprises less than 1 ppmw of paratoluic acid.

13. The invention of claim 11 , wherein the organic-depleted liquid water stream comprises less than 0.05 wt % methanol.

14. The invention of claim 11 , wherein the organic-depleted liquid water stream comprises less than 0.05 wt % methyl acetate.

15. The invention of claim 1 wherein the purification zone comprises a hydrogenation reactor.

16. The invention of claim 1 wherein the purifying comprises contacting an aqueous solution that comprises at least a portion of the crude aromatic carboxylic acid and at least a portion of the organic-depleted liquid water stream with hydrogen in the presence of a catalyst.

17. The invention of claim 1 , further comprising separating a purification mother liquid from the purified aromatic carboxylic acid.

18. The invention of claim 14 , further comprising transferring the purification mother liquor to a waste water treatment facility.

19. The invention of claim 14 , wherein the purification mother liquor is not used as reflux to the separation zone.

Assignees

• Bp Corp North America Inc

Inventors

• Bartos Thomas M

Classifications

• C07C63/26

  1,4 - Benzenedicarboxylic acid · CPC title

• C07C51/487 Primary

  by treatment giving rise to chemical modification (by chemisorption C07C51/47) · CPC title

• C07C51/42

  Separation; Purification; Stabilisation; Use of additives · CPC title

• C07C51/265

  having alkyl side chains which are oxidised to carboxyl groups · CPC title

• C07C51/50

  Use of additives, e.g. for stabilisation · CPC title